For some devices it is desirable to have a flat die. For example, sensing devices, such as focal plane arrays, can include die that can have sensors and/or circuitry. Conventional techniques for attempting to achieve flat die, e.g., to remove bow in the die, may include the use of glass beads in an epoxy bondline to control thickness. Weights can be used to flatten the device after epoxy application. However, some known techniques to remove bow in a die may put an assembly, such as focal planes, at risk, such as due to weight contact with optical surface.